Simple flesh wounds have already been referred to both in respect to their nature and treatment in the commencement of this essay. It is in connection with fractures of bones and their proper treatment that the interest of surgeons is chiefly attracted in gunshot wounds of the extremities. From the nature of the injuries, already described, to which bones are subjected by the modern weapons of war, together with the irreparable nature of the wound in the softer structures, except after a long process of suppuration and granulation, as well as from the usual circumstances of military life, it might be anticipated that difficulty would often arise in determining which of the double set of risks and evils—those attending amputation, and those connected with attempts to preserve the limb with a profitable result—would be least likely to prove disadvantageous to the patient. Experience in such injuries has established certain rules which are now generally acted upon; some still remain _sub judice_. Although the subject of pyemia is considered in its general bearings elsewhere, it is right to mention here that this serious complication, as met with in gunshot wounds, appears to be especially induced by injuries of bones, particularly those of long bones in which the medullary canal has been laid open and extensively splintered. Several circumstances probably conduce to this result: the prolonged suppurative action during the removal of sequestra, the irritation caused by sharp points and edges, sometimes increased by transport from primary to secondary hospitals, the patulous condition of veins in bones leading to thrombosis, being its chief local sources; while depressed vital power from any cause, and continued exposure to an impure atmosphere from the congregation of numerous patients with suppurating wounds, are the principal agents in producing the state of constitution favorable to its development and progress. Unless the hospital miasmata engendered in this way are constantly removed as they arise, or very greatly diluted by proper ventilation, it is almost impossible that patients laboring under severe wounds of the extremities with comminuted bony fractures can be long saved from septicemia and pyemia; and these, when they supervene, rarely lead to any but a fatal termination. The different conditions of hospital air, which in one set of cases lead to the appearance of hospital gangrene, in another set of pyemia, are not properly understood; but from the frequency with which the latter complication follows wounds of bones, it would seem that an especial influence is exerted by the local peculiarities of these injuries already mentioned. However, observation would also lead to the belief that certain individuals are much more predisposed to pyemic action than others placed under similar circumstances. Occasionally, in gunshot injuries of bones, where no splintering has occurred, but only a small portion of the periosteum